中文摘要
中国于 2021 年启动了全国性的强度型（rate-based）碳市场。该市场覆盖全球最大的二氧化碳排放国，其履约取决于碳排放强度而非绝对总量上限。我们借鉴强度型体系的理论文献，提供了关于早期实践者的首个实证证据。利用基于卫星影像的电厂层面数据和机器学习方法，我们发现，相对于低效电厂，高效电厂的发电量和二氧化碳排放量增加了约 5%。由于该碳市场规制了中国几乎所有燃煤电厂，我们聚焦于电厂效率带来的差异化反应，未发现排放强度出现差异化下降的证据（尽管这些估计并不精确）。相对于没有碳市场的印度尼西亚和菲律宾的燃煤电厂，中国的高效电厂同样增加了排放，而其低效电厂的估计值很小且不显著。这一反应模式表明，高效电厂的排放增加超过了从低效电厂的替代转移。凸显对中国更高效电厂的生产刺激作用的是，相对于低效电厂，高效电厂下风向的空气质量出现恶化，损害了中国相对清洁地区的空气质量。如果中国的目标是减少碳排放，则需要在现有体系内收紧基准值，或者采用一种不同时激励电力生产的替代体系。
Abstract
China launched a nationwide, rate-based carbon market in 2021. Covering the world’s top CO2 emitter, compliance depends on the intensity of carbon emissions rather than an absolute cap. We draw on the theoretical literature of rate-based systems to provide the first empirical evidence on an early adopter. Using plant-level data from satellite imagery and machine learning methods, we find that high-efficiency power plants increased electricity generation and CO2 emissions by approximately 5% relative to low-efficiency plants. Because its carbon market regulates nearly all coal plants in China, we focus on the differential responses by plant efficiency, finding no evidence of a differential reduction in emission intensity (though these estimates are imprecise). Relative to coal plants in Indonesia and the Philippines, which had no carbon market, China’s high-efficiency plants also increased emissions, while the estimate for its low-efficiency plants is small and insignificant. This pattern of responses suggests that emissions increases of high-efficiency plants exceeded substitution away from low-efficiency plants. Underscoring the production stimulus to more efficient Chinese plants, air quality worsened downwind of high- efficiency plants relative to low-efficiency plants, compromising air quality in relatively clean areas of China. If China's goal is to reduce its carbon emissions, then benchmarks will need to be tightened within the existing system or an alternative system that does not simultaneously incentivize electricity production will need to be adopted.